GB377059A - Improvements in or relating to safety devices for elevators - Google Patents

Abstract

377,059. Safety devices for lift cages. WESTINGHOUSE ELECTRIC & MANUFACTURING CO., East Pittsburg, U.S.A.- (Assignees of Dunlop, J. ; 513, South Prospect Avenue, Park Ridge, Illinois, U.S.A.) Nov. 18, 1931, No. 31987. Convention date, Nov. 26, 1930. [Classes 78 (iii) and 78 (v).] In an elevator safety device of the kind in which stationary guide rails are gripped by members on the elevator, the means for actuating the rail-gripping members is controlled by means directly responsive to an abnormal deceleration of the elevator whereby a predetermined deceleration is automatically maintained. When overspeeding of the car C, Fig. 1, occurs the governor rope 11 is held stationary by pivoted grips 17, 18, which are .actuated by the governor sleeve through a lever 19 and rope 20. During continued movement of the car, a ball 14 on the rope 11 becomes disengaged from a spring clip 15 on the car and a rope 27, connected to the rope 11, is unreeled from a drum 31, Fig. 3, underneath the car so as to rotate the drum and move threaded shafts 38, 43 outwards. Wedges 36, 37, connected directly to the shaft 38 and by a piston 41 in an oil-containing cylinder 42 to the shaft 43 respectively, engage pivoted jaws 32, 33, and move shoes 51, Figs. 2 and 3, slidably mounted therein, against guide rails 34, 35. If the retardation exceeds a predetermined rate, the inertia of a weight 47 ,tilts a lever 46 and opens a spring-controlled valve 44 to release the pressure in the cylinder 42. The pressure exerted by the wedges 36, 37, thus diminishes until the deceleration is reduced to the predetermined rate when the valve 43 closes. If the speed of the car is not reduced sufficiently as it approaches a terminal, a roller 54 on the car engages a pivoted cam 24, projected in the hatchway by a rope 21 connected to the governor sleeve, whereby a lever 53, rotated clockwise, pulls a rope 55, Fig. 2, and lifts the shoes 51 into engagement with the rails 34, 35, to retard the movement of the car. If, however, the speed is reduced sufficiently the governor will permit the cam to retract from the hatchway so as to allow free passage of the roller 54. If a car overruns a terminal and approaches the bottom of the hatchway, the shoes 51 engage an enlarged portion 58, Fig. 2, of the guide rails and the maximum allowable braking is applied to stop the car.